Fast acting clamp



July 9, 1963 mwm 3,096,975

FAST ACTING CLAMP Filed June 23, 1960 1NVENTOR.

\s' MILTON IRWIN BY W 4. wieialmwn i": 7 8 09d PM ATTORNEYS 3,096,975 FAST ACTING CLAMP Miiton Irwin, 4609 Nicollet Ave., Minneapolis, Minn. Filed June 23, 1960, Ser. No. 38,337 2 Claims. (ill. 269-169) This invention relates to workpiece holding apparatus and more specifically relates to a quick-acting clamp for securely holding one or more workpieces in a predetermined position.

Various types of clamping devices have been known in the past, including several types of C-clamps. In the past conventional C-clamps have employed a threaded shaft which is screwed against the workpiece or workpieces to hold the same in a predetermined position. Such types of conventional C-clamps have had numerous disadvantages. In the first place such (J-clamps are slow to operate and remove and when a number of such clamps are to be applied to one or more workpieces the time consumed in applying and removing the clamps is considerable. Obviously, in industrial applications the time consumed is expensive.

Another distinct disadvantage of clamping devices known in the past is that only a limited amount of pressure can be exerted against the workpiece or workpieces when clamped, depending upon the nature of the screw threads on the shaft and the means by which the shaft is turned. It is difficult to obtain any uniformity of holding force against the workpiece.

An object of my invention is to provide a new and improved clamping device of simple and inexpensive construction and operation.

Another object of my invention is to provide a novel clamping apparatus which may be readily and easily operated for applying the desired pressure against the workpiece or workpieces to be clamped.

Still another object of my invention is the provision of an improved clamping apparatus which is adapted to exert varying amounts of force against the workpiece or workpieces to be clamped.

A further object of my invention is to provide new and novel clamping apparatus which is adapted to exert a uniform clamping force against the workpiece or workpieces to be held in successive operations of the apparatus.

A still further object of my invention is the provision of a novel and improved clamping apparatus which is readily adaptable for use with workpieces of varying shapes and sizes so as to eificiently and efiectively cause secure holding of the workpiece or workpieces regardless of their shapes.

These and other objects and advantages of my invention will more fully appear from the following description made in connection with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views and in which:

FIG. 1 is an elevational view, partly broken away and partly shown in section, of the invention;

FIG. 2 is a detail section taken at 22 in FIG. 1;

FIG. 3 is an enlarged detail section view of a portion of the apparatus on a line approximately as indicated at 3--3 in FIG. 2;

FIGS. 4-6 are detail elevation views of modified forms of a portion of the invention;

tates Patent 3,096,975 Patented July 9, 1963 ice FIGS. 7-10 are detail elevation views of still additional modifications of a portion of the invention; and

FIG. 11 is an elevation view partly broken away and partly shown in section of an additional modified form of the invention.

In the form of the invention shown in FIGS. 1 and 2, the clamping apparatus is designated in general by numeral 10 and includes a rigid and substantially C-shaped body 11 having a base or stationary jaw 12 formed integrally therewith and also having a bifurcated upper portion 13 defining spaced and parallel horizontally extending legs 14 and 15 defining an open armaturereceiving space 16 therebetween.

A smooth vertically slidable shaft 17 has an enlarged head 18 on the upper end thereof and has the lower end portion 17a thereof extending toward the stationary jaw 12 for clamping workpieces W and W together thereon.

The lower leg 14 has a shaft aperture 14a therein, and the upper leg 15 has a threaded nut-receiving opening 15a therein. An externally threaded nut 19 has a knurled and enlarged upper end 20 and is threaded into the opening 15a and the nut 19 has a smooth opening 21 formed therethrough for receiving the shaft 17 in sliding relation. The shaft is thereby mounted for vertical sliding movement toward and away from the workpieces. The shaft 17 has a removable jaw-forming foot 21 threaded at 21a onto the threaded corresponding lower end 1701 of the shaft to provide a suitable workpiece engaging surface 21b in confronting relation with the base of stationary jaw 12.

Means are provided for releasably securing the shaft in a predetermined position and for forcibly urging the shaft 17 against the workpieces in order to clamp the workpieces with a desired force or pressure. In the form shown such means include a flat and rigid plate-like armature 22 with a shaft-receiving opening 23 therethrough and of such size as to receive the shaft 17 in close fitting and slidable relation when the armature 22 is in the horizontal position shown in FIGS. 1 and 3. The opening 23 is formed so that the outer and lower peripheral sidewall portion 23a thereof and the upper and inner peripheral sidewall portion 23b are oriented substantially normal to the upper and lower surfaces of the armature 22. The outer and upper peripheral sidewall portions 230 of the opening and the lower and inner peripheral sidewall portions 23d of the opening are oriented at a slight angle, or are slightly oblique to the normal with reference to the upper and lower surfaces of the armature 22. It has been found successful in one instance to orient the sidewall portions 230 and 23d at an angle of approximately 6 from the normal with respect to the upper and lower surfaces of the armature 22.

The inner end of armature 22 extends to a position beneath and partially within the handle-receiving slotlike opening 24 in the upper leg 15 of the body. The upper surface of armature 22 is recessed at 22a so as to permit the uppermost central portion 22b thereof fit upwardly to a small degree into the opening 24. A swingable or rotatably oscillatable cam 25 engages the portion 22b of armature 22 and is swingably mounted on pivot pin 26, the ends of which are fixed in suitable apertures in the sides of leg '15. It will be noted that the cam 25 is asymmetrically formed around the center of the pivot 26 so as to produce a downward movement of the portion 22b of the armature when the cam is swung in a clockwise direction from the full line position shown in FIG. 1.

The cam 25 is connected with a cam-operating handle 27 and in the form of the invention shown, the handle 27 is integral with the cam 25.

A coil spring 28 is applied around shaft 17 in loosefitting relation and the lower end of spring 28 bears against the lower leg 14 of the body. The upper end of spring 28 bears against the outer end portion of armature 22 so as to normally urge the outer end of the armature upwardly against the lower end 19a of the nut 19.

A cover plate 29 is substantially U-shaped and is wrapped around the outer ends of legs 14 and 15 in enclosing relation with the space 16 and is secured at the sides of the body as by screws 30.

A spatter shield 31 of slightly shorter length than the shaft 17 is secured thereto by inwardly extending shaftengaging tabs 32 at the upper and lower ends thereof which hold the shield on the shaft and permit the shield to be applied to and removed from the shaft with a snaplike action.

In operation, the armature 22 is released from the shaft 17 so as to permit free sliding of the shaft in an upward and downward direction when the armature is in the horizontal position shown in FIG. 1. The outer end of the armature bears upwardly against the lower end of nut 19 and the inner end generally bears against the cam 25. As the workpieces W and W are being applied onto the base or stationary jaw 12, the shaft may be moved upwardly to the position A shown in dot-dash lines so as to move the foot 21 upwardly correspondingly. The shaft 17 will be retained in this position by the very slight frictional relationships of the parts.

When the workpieces W and W have been properly positioned, or conversely, when the clamp has been properly positioned in relation to the workpieces, the shaft 17 will be manually pushed downwardly so as to move the foot 21 against the workpiece W so that the shaft and foot assume the position shown approximately in full lines in FIG. 1. The handle 27 is then swung downward from the full line position to the dotted line position B. This swinging of the handle will rotate the cam 25 which will urge the inner end of the armature 22 toward the workpiece. The pressure exerted by spring 28 against the outer end of the armature 22 will cause the armature to tilt to the inclined or oblique position shown in dotted lines B so that the sidewall portions 230 and 23d of the opening 23 tightly engage the shaft periphery in frictional, locking relation. The locking of the armature to the shaft is accomplished during the initial stages of swinging of the handle 27 and during the final stages of swinging handle 27 into the dotted position B, the entire armature and the shaft, which is now locked to the armature, move downwardly to the dotted position B. It will be noted that in the dotted position B the armature 22 has been moved downwardly away from the lower end 19a of the nut 19 and the bottom of the foot 21 has moved downwardly toward the stationary jaw 12. It will therefore be seen that the swinging of the handle 27 from its full line position to the dotted line position B locks the shaft to prevent any upward movement thereof and also produces a downward movement of the shaft and foot in order to exert clamping pressure or force against the workpieces.

It will be understood that it may be desirable to change the increment of downward movement of foot 21 as the handle is swung downwardly to the position B, depending upon the nature and size of the workpieces W to be clamped together. In order to vary the increment of movement of the shaft and foot, the nut 19 may be adjusted slightly by turning it upwardly or downwardly. In the event that the nut 19 is adjusted slightly downwardly, the armature 22 is also moved downwardly slightly against ing of handle 27 from its full line position to the dotted position B thereof, produces a smaller increment of downward travel of the foot 21 than had previously been obtained. In a similar manner if the nut 19 is adjusted upwardly, the increment of downward travel of shaft 17 and foot 21 is increased.

In this respect it will be understood that if the workpieces W and W are substantially flat metal plates, only a small increment of downward travel of shaft 17 and foot 21 will be necessary in order to produce a very substantial clamping pressure against the workpieces. On the other hand, if the workpieces are metal plates or elongate rods which are substantially warped, then a substantial increment of downward travel of the shaft may be necessary in order to bring the workpieces into engagement with each other.

In FIG. 4 is shown a foot 21 having a V-shaped notch N in the bottom thereof for engaging a round piece of stock or workpiece. The foot 21 is threaded onto the shaft 17 in the manner shown in FIG. 1.

'In FIG. 5 is shown another form of foot 21" having a V-shaped bottom surface V for holding a piece of angle stock in predetermined position.

in FIG. 6, the foot 21" of FIG. 5 is shown, and in this form a demountable base 12' is applied to the body 11 a and may comprise an inverted cup-like element receiving the pressure of spring 28; and in this instance, the swingthe conventional base 12 therein and having a V-shaped nut V therein for receiving the outside corner of an angle bar.

FIG. 7 shows still another shape of foot 213 having a sharp edge E for engaging and holding a correspondingly shaped workpiece.

In FIG. 8 the foot 21-4 has a ball b and flat bottomed swivel foot s thereon.

In FIG. 9 the foot 21-5 has a smoothly rounded tip R for engaging a correspondingly shaped workpiece.

In FIG. 10 a foot 216 is provided with a smoothsurfaced interior chamber 0 for receiving the smooth lower end of shaft 17 which is grooved at 17a and is provided with a retaining ring 17b which bears against the inner surface 0 of the foot.

The form of the invention shown in FIG. 11 is similar in many respects to the form of the invention shown in FIG. 1 and is provided with a stationary jaw or base 42, but in this instance the body 40 and stationary jaw 42 are interconnected through the mediumof a work bench or table 43 to which both the body and stationary jaw are secured as by bolts 41. In the form of the in vention the upper body portion defines the upper and lower legs 44 and 45 respectively, and in this form of the invention, side walls 46 are also formed integrally with the body and extend between the upper and lower legs 44 and 45 to define the interior chamber area 47 and to rigidly mount a support or shelf 48 intermediate the upper and lower legs 44 and 45. The shaft 49 slidably extends through a bushing 50 and through the adjustable nut 51, both of which are threaded into the respective legs. A spring 52 bears upwardly against the armature 53 which also receives the shaft 49 therethrough in a manner similar to the arrangement previously described in connection with FIG. '3, and the inner end of the armature is engaged and acted upon by a swinging cam 54 which is pivoted on pin 55 in the slot-like opening 56 of the body to be operated by the handle 57 which is integral with the cam. It will be seen that the spring 52 is supported on the shelf 48.

The portion of the apparatus described in FIG. 11 operates substantially similarly to the corresponding apparatus of FIG. 1.

In addition a handle-swinging lever 58 is swingably mounted on a pin 59 in a recess 60 of the body 10 and the outer end of lever 58 engages the handle 57. A coiled spring 61 which bears against the bottom of recess 60 and extends into a recessed portion 62 of the lever 58, is wrapped around the pin 59 and bears against the lever 60 so as to normally urge the lever in a counter-clockwise direction to thereby tend to swing the handle up.

A second armature 63, substantially similar in construction to the armature 53 is provided on the shaft beneath the shelf 48. A second spring 64 bears against the stationary bushing 50 and upwardly against the outer end of the armature 63. A cam 64 is afiixed to a rot-atable shaft 65 which is journalled in suitably provided bearing apertures in the side walls 46 of the body and which is also afiixed to a handle or lever 66 at the exterior of the wall 46 to facilitate operation of the cam 64 as desired.

In the operation of this form of the invention, if cam 64 is swung through an arc of approximately 90 from that shown in FIG. 11, the operation of the apparatus will be substantially identical to that shown in FIG. 1.

Swinging of the handle downwardly will first cause the armature 53 to lock against the shaft 49, and will then produce a downward movement of the shaft and armature to produce the small increment of downward movement of the foot against the workpiece.

In this form of the invention after the cam 64 is svwlng to the position shown in FIG. 11, the armature 63 is tilted and locked against the shaft 49 to prevent any upward travel of the shaft 49. The conventional downward swinging of the handle 57 will lock the armature 53 to the shaft and will move the shaft and armature downwardly through a small increment of travel. When the shaft 49 is moving downwardly, the outer end of armature 63 moves downwardly slightly and allows the shaft 49 to slide downwardly therethrough, but when the downward movement of the shaft 49 is terminated, the armature 63 again locks against the shaft and prevents any upward movement thereof. The handle 57, after release, will then be swung upwardly by operation of lever 58, and of course the armature 53 will move upwardly against the nut 57 and will be in unlocked relation with the shaft. Downward swinging of handle 57 will produce another increment of downward travel of shaft and armature 53, and again, the armature 63 will allow the shaft 49 to travel downwardly but will restrain any upward movement.

It will be seen that handle 57 may be oscillated to produce a sequence of incremental movements of the shaft 49 and the foot so that regardless of the nature of the workpiece to be clamped, all of the necessary slack may be taken up so as to produce the desired clamping action and so as to produce the desired pressure against the workpiece or workpieces.

To release the workpieces in the form of the invention in FIG. 1 the handle 27 is merely raised, whereupon the pressure against the workpiece is relieved and shaft 17 may be manually lifted.

To release the workpiece in the form shown in FIG. 1='1, the handle 57 will be swung downwardly to the position shown to relieve the holding force on armature 63, whereupon the lever 66 and cam 64 may be swung through a quarter of a turn and when the handle 57 is again raised, the workpiece will be released. The shaft 49 may be then manually lifted.

It will, of course, be understood that various changes may be made in the form, detail, arrangement and proportion of the parts without departing from the scope of my invention which consists of the matter described herein and set forth in the appended claims.

What is claimed is:

l. A clamping device comprising a rigid c-shaped body having forwardly projecting upper and lower portions in confronting relation with each other, said lower body portion having an upwardly facing stationary jaw thereon, the upper portion of said body being bifurcated and defining a pair of forwardly extending and spaced upper and lower legs having vertically aligned openings therein and having front ends, said legs defining an unobstructed space therebetween, a longitudinally movable shaft extending toward said stationary jaw to clamp a workpiece thereon, said lower leg receiving and guiding said shaft through the opening therein, an externally threaded sleeve receiving and guiding the shaft therein and being threaded into the opening in said upper leg, said sleeve projecting downwardly from said upper leg, an elongate plate-like armature in said space between said legs and having a forward end with an aperture extending transversely therethrough and slidably receiving said shaft in close-fitting relation to lock against the shaft when the armature is tilted, said armature having .a rear end to be tilted and moved downwardly toward the stationary jaw to lock the armature to the shaft and move the shaft toward the jaw, said upper leg having a slot aperture therethrough and extending in a fore-and-aft direction, said slot aperture having an inner end confronting the rear end of the armature to provide access thereto, a spring between said lower leg and the forward end of the armature and urging the armature away from the stationary j-aw, an upright elongate handle having an inner cam-ming end portion projecting through said slot aperture and engaging the rear end of the armature, pivot means mounting said handle in the slot aperture for swinging rearwardly and downwardly to a substantially horizontal position, said slot aperture having handleengaging end surfaces respectively engaging the handle when the handle is swung to upright and horizontal positions, the inner camming end portion of the handle being asymmetrically shaped about said pivot means and cooperating with the spring to produce tilting and downward and upward movement of the rear end of the armature when the handle is successively swung in opposite directions, and a substantially U-shaped cover having rearwardly extending side panel portions lying along said upper and lower legs and enclosing said space therebetween and said cover also having an intermediate portion interconnecting said side panel port-ions and being wrapped around the front ends of said legs.

2. A clamping device comprising a rigid C-shaped body having forwardly projecting upper and lower portions in confronting relation with each other, said lower body portion having an upwardly facing stationary jaw thereon, the upper portion of said body being bifurcated and defining a pair of forwardly extending and spaced upper and lower legs having vertically aligned openings therein and having front ends, said legs defining an unobstructed space therebet-ween, a longitudinally movable shaft extending toward said stationary jaw to clamp a workpiece thereon, said lower leg receiving and guiding said shaft through the opening therein, an externally threaded sleeve receiving and guiding the shaft therein and being threaded into the opening in said upper leg, said sleeve projecting downwardly from said upper leg, an elongate plate-like armature in said space between said legs and having a forward end an aperture extending transversely therethrough and slidably receiving said shaft in close-fitting relation to lock against the shaft when the armature is tilted, said armature having a rear end to be tilted and moved downwardly toward the stationary jaw to lock the armature to the shaft and move the shaft toward the jaw, said upper leg having a slot aperture therethrough and extending in a fore-and-aft direction, said slot aperture having an inner end confronting the rear end of the armature to provide access thereto, a spring between said lower leg and the forward end of the armature and urging the armature away from the stationary jaw, an upright elongate handle having an inner camming end portion projecting through said slot aperture and engaging the rear end of the armature, and pivot means mounting said handle in the slot aperture for swinging rearwardly and downwardly to a substantially horizontal position, said slot aperture having handleengaging end surfaces respectively engaging the handle when the handle is swung to upright and horizontal positions, the inner camming end portion of the handle being 7 asymmetrically shaped about said pivot means and cooperating With the spring to produce tilting and downward and upward movement of the rear end of the armature when the handle is successively swung in opposite directions.

References Cited in the file of this patent UNITED STATES PATENTS 1,599,895 John Sept. 14, 1926 8 Holman Nov. 12, 1940 Lucker Nov. 11, 1941 Purdy Jan. 12, 1943 Gilbert June 7, 1949* *Lile July 8, 1952 Heinrich Oct. 7, 1952 Sprink Aug. 12, 1958 Sagerty Dec. 9, 1958 

1. A CLAMPING DEVICE COMPRISING A RIGID C-SHAPED BODY HAVING FORWARDLY PROJECTING UPPER AND LOWER PORTIONS IN CONFRONTING RELATION WITH EACH OTHER, SAID LOWER BODY PORTION HAVING AN UPWARDLY FACING STATIONARY JAW THEREON, THE UPPER PORTION OF SAID BODY BEING BIFURCATED AND DEFINING A PAIR OF FORWARDLY EXTENDING AND SPACED UPPER AND LOWER LEGS HAVING VERTICALLY ALIGNED OPENINGS THEREIN AND HAVING FRONT ENDS, SAID LEGS DEFINING AN UNOBSTRUCTED SPACE THEREBETWEEN, A LONGITUDINALLY MOVABLE SHAFT EXTENDING TOWARD SAID STATIONARY JAW TO CLAMP A WORKPIECE THEREON, SAID LOWER LEG RECEIVING AND GUIDING SAID SHAFT THROUGH THE OPENING THEREIN, AN EXTERNALLY THREADED SLEEVE RECEIVING AND GUIDING THE SHAFT THEREIN AND BEING THREADED INTO THE OPENING IN SAID UPPER LEG, SAID SLEEVE PROJECTING DOWNWARDLY FROM SAID UPPER LEG, AN ELONGATE PLATE-LIKE ARMATURE IN SAID SPACE BETWEEN SAID LEGS AND HAVING A FORWARD END WITH AN APERTURE EXTENDING TRANSVERSELY THERETHROUGH AND SLIDABLY RECEIVING SAID SHAFT IN CLOSE-FITTING RELATION TO LOCK AGAINST THE SHAFT WHEN THE ARMATURE IS TILTED, SAID ARMATURE HAVING A REAR END TO BE TILTED AND MOVED DOWNWARDLY TOWARD THE STATIONARY JAW TO LOCK THE ARMATURE TO THE SHAFT AND MOVE THE SHAFT TOWARD THE JAW, SAID UPPER LEG HAVING A SLOT APERTURE THERETHROUGH AND EXTENDING IN A FORE-AND-AFT DIRECTION, SAID SLOT APERTURE HAVING AN INNER END CONFRONTING THE REAR END OF THE ARMATURE TO PROVIDE ACCESS THERETO, A SPRING BETWEEN SAID LOWER LEG AND THE FORWARD END OF THE ARMATURE AND URGING THE ARMATURE AWAY FROM THE STATIONARY JAW, AN UPRIGHT ELONGATE HANDLE HAVING AN INNER CAMMING END PORTION PROJECTING THROUGH SAID SLOT APERTURE AND ENGAGING THE REAR END OF THE ARMATURE, PIVOT MEANS MOUNTING SAID HANDLE IN THE SLOT APERTURE FOR SWINGING REARWARDLY AND DOWNWARDLY TO A SUBSTANTIALLY HORIZONTAL POSITION, SAID SLOT APERTURE HAVING HANDLEENGAGING END SURFACES RESPECTIVELY ENGAGING THE HANDLE WHEN THE HANDLE IS SWUNG TO UPRIGHT AND HORIZONTAL POSITIONS, THE INNER CAMMING END PORTION OF THE HANDLE BEING ASYMMETRICALLY SHAPED ABOUT SAID PIVOT MEANS AND COOPERATING WITH THE SPRING TO PRODUCE TILTING AND DOWNWARD AND UPWARD MOVEMENT OF THE REAR END OF THE ARMATURE WHEN THE HANDLE IS SUCCESSIVELY SWUNG IN OPPOSITE DIRECTIONS, AND A SUBSTANTIALLY U-SHAPED COVER HAVING REARWARDLY EXTENDING SIDE PANEL PORTIONS LYING ALONG SAID UPPER AND LOWER LEGS AND ENCLOSING SAID SPACE THEREBETWEEN AND SAID COVER ALSO HAVING AN INTERMEDIATE PORTION INTERCONNECTING SAID SIDE PANEL PORTIONS AND BEING WRAPPED AROUND THE FRONT ENDS OF SAID LEGS. 